Tightening device for belt-pulleys



(No Model.) f

N. W. HQLT. V'.lGfETENINE DEVICE EOE BELT EUELEYS. Y No. 273,081. Patented IFeb-27. 1883.

ai lill lll.

Winamax'.

UNITED STATES PATENT OFFICE.

t NOAH W. HOLT, OF BUFFALO, NEW YORK.

TIGHTENING DEVICE FOR BELT-PULLEYS.

SPECIFICATION forming part of Letters Patent No. 273,081, dated February 27, 1883.

Application filed October 2l, 1882. (No model.)

To all whom it may concern:

Be it known that I, NOAH W. HOLT, ofthe city of Buffalo, in the county of Erie and State of New York, have invented new and useful Improvements in Tightening Devices for Belt- Pulleys, of which the following is a specification.

This invention relates more particularly to improvements in mechanism whereby belt-pulleys are adjusted to regulate the tension of the belt; a-nd the object of my invention is to so constructl the mechanism that the desired adjustment can be quickly effected, and so that the pulley is securely held in position when adjusted.

My invention consists, to that end, of the peculiar construction of the adjusting mechanism, which will be hereinafter fully described, and pointed out in the claims.

In the accompanying drawings, Figure l is a side elevation of a belt-pulley provided with myimproved belt-adj usting mechanism. Fig. 2 is a vertical section in line ac x, Fig. 1. Fig. 3 is a horizontal section in line y y, Fig. 1, ou an enlarged scale.

Like letters of reference refer to like parts in the several figures.

A represents the belt-pulley, a the hub of the same, and b a hollow shaft to which the' belt-pulley is firmly secured.

O O represent movable boxes or bearings in which the ends of the hollow shaft b rotate.

D represents the basev or bed-plate of the supporting-frame, and E E two standards rising from the bed-plate D on each side of the pulley. The standards E E are provided on their inner vertical faces `with vertical grooves e, which form ways in which the boxes O O move up and down in adjusting the pulley.

The boxes C C are provided with projecting ribs c, which fit into grooves e of the standards E E and hold the boxes against lateral displacement.

j f are vertical rack-bars formed on the standards E E', and g g are gear-pinions which mesh with the rack-bars ff, and are secured to a horizontal shaft, h. The latteris arranged axiallyin the hollow shaft b, and turns in con#l k ltrepresent pawls hung on the shaft It and engaging with the rack-bars ff, so as to pre-` vent retrograding movementof the pulley after it has been adjusted. Y

In Figs. l and 2 the pulley is shown in its highest position. lBy turning the hand-wheel I in the direction of the arrow in Fig. l the pinions g g move downwardly on the rack-bars fj', whereby the shaft h and the movable boxes C, attached thereto, are also lowered. The movable bearings O carry the hollow shaft b and the pulleyAwith them,and bythis means the pulley is moved downwardly between the standards. The pawls lc k engage with the raclrbarsf and hold the shaft h and the supporting parts of the pulley connected therewith in the position in which these parts have been placed by rotating the hand-wheel. By turning the hand-wheel in an opposite direc tion the pullej1 is moved upwardly. The arrangement of the pawls shown in the drawings supposes that the' belt runs around the lower side of the pulley, so that the pressure of the belt againstthe pulley is in an upward direction. If the belt runs around the upper side of the pulley, so that the pressure operates in a downward direction, the pawls are arranged on the lower sides of the pinions.

l claim as my invention-- 1. The combination, with a pnlley,'of a supporting-frame provided with rack-bars ff, a shaft provided with pinions g g, meshing with said rack-bars, and mechanism whereby the pulleyis connected with said shaft and caused to follow its movements as the shaft is moved back and forth by the rotation of the pinions on the rack-bars, substantially as set forth.

2. 'Ihe combination, with a supporting-frame provided with rack-bars f f, of a shaft, It, provided with pinions g g, movable boxes C, hollow shaft b, and a pulley secured to said hollow shaft, substantially as set forth.

3. The combination, with the standards E E', provided with rack-bars f f and parallel grooves c, of the shaft h, provided with pinions g g, boxes C, provided with ribs c, hollow shaft b, anda pulley secured thereto, substantially as set forth.

NOAH W. HOLT.

Witnesses:

JNO J. BONNER,

CEAS. F. GEYER. 

